Technical Field
The present disclosure relates to the field of optical modules, and in particular, to an optical module.
Related Art
Optical modules have become an essential part of electronic and optoelectronic devices in communications systems. Printed circuit boards are important part of an optical module, and are used to hold and connect electronic and optoelectronic components. With the development of electronic fabrication technologies, wiring density in printed circuit boards has become increasingly higher, and printed circuit boards has become more complex. Higher wiring density in a printed circuit board may cause increased crosstalk between electric signals including differential signals during their processing and transmission.
Differential signal transmission technology differs from a conventional signal transmission method. In conventional signal transmission, an electric signal is transmitted on a single signal line and a reference ground line. In differential signal transmission, a signal is transmitted on two differential lines as differential signals. The differential signals have the same amplitude but opposite phases and polarities. With limited space and high wiring density on a printed circuit board, crosstalk may be generated between pairs of differential signals. Crosstalk represents noises caused by a capacitive or inductive coupling between signal lines. Crosstalk degrades signal integrity. As such, reducing crosstalk between electric transmission lines and signals is essential for ensuring signal integrality. Differential signals are particularly sensitive to crosstalk. Large crosstalk causes loss of information during transmission, leading to a high transmission bit error rate.